The present invention relates generally to apparatus for cross-lapping a textile material in order to form a batting of indefinite length. More particularly, the present invention concerns apparatus for making a batting from a high denier tow of substantially continuous filaments.
In the past, cross-lapping devices have been developed in order to form a batting of staple fibers. By virtue of the relatively short length of staple fibers, the material must be vertically supported throughout processing and particularly during lay down in order to avoid tension that may cause separation, or otherwise render the material unfit for use in cross-lapping process and apparatus. In fact, these cross-lapping devices have been developed for accomodating the idiosyncrasies of staple fiber material and are unsuited to use for continuous filament materials.
When dealing with continuous filament materials, such apparatus is, therefore, unnecessarily complex and consequently expensive. One aspect of the unnecessary complexity is that a substantially continuous filament material in the form of a high denier tow is capable of self support during essentially horizontal runs. Thus, vertical support for the tow is not necessary. Another aspect of handling continuous synthetic filaments concerns the development of static electricity during processing. For example, when static charges accumulate on the filaments, the individual filaments repel one another making it difficult to deposit the filaments in a controlled manner.
There exists a cross-lapping device for continuous filament material which employs an arcuately swinging chamber which directs the material to a conveyor. But, where the chamber itself experiences arcuate movement, the tow of continuous filament material is cast at the receiving surface with varying unsheltered length and variable tension. Casting in that device also uses air currents to aid placement of filament material as it is being deposited. These air currents and tensile strength variations make a difficult task in obtaining a uniform density batting with precision edges. Where material lay down adjacent the batting edges does not provide a straight precision edge, some further processing of the batting is required in order to provide an acceptable product for subsequent use.
One cross-lapping device, has made use of a reciprocating carriage disposed transversely above a receiving conveyor, with the carriage having a pair of counter rotating rolls: one roll being resiliently surfaced, the other being steel. It has been found, however, that this combination of two dissimilar materials for the processing carriage generates static electricity in the tow of continuous filament material causing difficulty in subsequent lay down during batting formation. Moreover, the filament material tends to adhere to the surface of the resilient roll and to become wrapped therearound. This wrapping phenomenon is commonly referred to as lapping. When lapping occurs, the throughput rate of tow is limited and, when lapping continues, machine must be shut down so as to clear the roll. Accordingly, a device which overcomes the combined problems of static electricity and lapping is a desirable improvement in the art.
Another difficulty encountered in connection with the known cross-lapping machines having a reciprocating carriage relates to the mechanism for effecting carriage reversals. The inertia of the carriage is an important factor in determining the speed and ease with which the reversals may be effected. Accordingly, it is important to have a carriage which is as light as possible so as to provide a minimum inertia that must be reversed at the end of each reciprocating stroke. In this connection, it is desirable to have a reversible drive system in continuously driving relationship to the carriage so that carriage motion can be controlled throughout the stroke and delays in starting movement are minimized. Such a device is to be sought since it can contribute to the increase in effective material feed rate and, simultaneously, provide both the uniform density and a rigidly controlled precision edge for the batting.
In view of the foregoing discussion, it will be apparent to those skilled in the art that the need continues to exist for a cross-lapping mechanism which overcomes the problems of the type discussed.